AUGUST 19TH, 1905.

THE AUTOCAR B 3ournal publiobe~ in tbe interests of tbe mecbanicall~ propelle~ roa~ carriage.

EDITED BY H. WALTER STANER.

No. 513. VoL. XV.] SATURDAY, AUGUST rgTH, 1905.

[PRICE 3D.

Tff E A UTOCAR.

(Published Weekly. )

Registered as a newspaper for transmission in the United Kingdom. Entered as second.class matter at the New York (N.Y.) Post Office.

EDITORIAL OFFICE :

COVENTRY.

PUBLISHING OFFICES:

20, TUDOR STREET, LONDON, E.C., ENGLAND.

CONTENTS.

NOTES: DOUBLE IGNITION- WATER-COOLED BRAKES USEFUL HINTS AND TIPS. By Lieut. Windham, R.N. L'l<NTENTE CORDIALE EN AUTOMOBILE (illustrated) ... THE TOURIST TROPHY THE HERKOMER T ROPHY AND BLEICHRODER RACE (illustrated)

PAGE 211-212 ... 213 214-215 ... 215 216-219

THE HALLE SPRING WHEEL-THE TRAINING OF MECHANIC-DRIVERS 219 THE 40 H.P. GEORGES-RICHARD-BRASIER (illustrated) 220-221 THE MOTOR BOAT TRIALS (illustrated) .. . 222-223 MOTOR YACHT CLUB RELIABILITY TRIALS: THE JUDGES' REPORT 223-224 CONTINENTAL NOTES AND NRws (illustrated): END OF THE G -B. Cup-

THE MAKERS' ATTITUDE-A TYRE RACE-TOURING TESTS-A TOURING CAR RACE 225-226 CORRESPONDENCE : U NREASONING PREJUDICE ] USTJFIED-THE

CARRIAGE BUILDERS' STATUS-OFFENSIVE EXHAUST-SLOWM0VING TRAFFIC-PRIMARY BATTERIES-RUTLAND POLICE AND MOTORISTS-HANDICAPPING AT BRIGHTON AND BLACKPOOLS UMMARY OF OTHER CORRESPONDENCE 227-229 THE THORNYCROFT TouRIST TROPHY CAR (illustrated) 230-231 THE MICHELIN NaN-SKID {illustrated) ... ..• 231 CASUAL COMMENTS. By A. J. Wilson.. . 232 THE NEW DucELLIER LAMP (illustra1ed) · ... 233 FLASHES 234-236 CLUB DOINGS : MIDLAND A.C. OPEN HtLL-CLIMB (illustrated)-SussEx

COUNTY A.C.-NORTH-EAST&RN AUTOMOBILE ASSOCIATIO ~-COUN-__ ., TRY GYMKHANA-LEICESTERSHIRE A.C. - D&RBY AKO DISTRICT A.C. HILL-CLIMB (illustrated)-CLUB FIXTURES... 237-238 ROAD WARNINGS (illustrated) 239-240

THE AUTOCAR" DIARY ...

... 240

"THE AUTOCAR" SUBSCRIPTION RATES. British Is les, I6s. Abroad (thin paper edition), 22s. Sd. per:annum.

I ( Notes. Double Ignition. A letter which we have received from a correspondent styling himself " Cylinder " brings up a matter of very considerable interest to quite a large percentage of motorists, i .e., to all who have high or low tension magneto with battery as a standby. Our correspondent tells us that he finds his car rw1s much better with both the ignitions firing at the same time, and this is the experience of the majority of those who have tried the experiment. When battery ignition is fitted as a standby to low tension magneto both can always be used simultaneously. This is also the case when the battery ignition is used in conjunction with high tension magneto, provided that a separate set of plugs is fitted for each system. In some cases, however, with high tension the ignition is fitted up so that one lot of plugs only is used, and then the two systems can only be used alternately, according to which is switched into operation. Quite apar:t from the extra power developed by running the two ignitions simultaneously many have found it advisable to do this to keep the standby ignition in order, as they have found when they have relied on the battery ignition and did not put it into operation till it was actually wanted, i.e., when the magneto showed signs of some derangement, it meant, when separate plugs were used, that they were so hopelessly fouled, even when they were on the exhaust side, that they all had to be thoroughly cleaned before a spark could be obtained, and then it was possible that the accumulator would be in a bad way, simply and solely through having been allowed to remain inactive. It is therefore necessary to use the standby ignition at times either separately or in conjunct;___,ll with the main system. In any ca.se, there is no doubt that on the majority of cars the engine develops more pvwer with double ignition. This is not, as many people imagine, due to any particular virtue in the combination of magneto and battery sparks, but rather to the fact that the two sparks instead of one result in the more rapid propagation of the explosion of the charge. Even in slow running engines the time available for the exploding of a charge is but an infinitesimal fraction , and the higher the speed of the engine the less is the fraction of time available.

Although the combustion of the charge is extraordinarily rapid it must take an appreciable time, and consequently if, to use a homely illustration, a fire is started from two points instead of one that fire will become a blaze much more quickly. In the case of the petrol engine, too, the more rapid propagation of the explosion also means more complete combustion. In other words, for a given size of 'engi11e and a given amount of fuel better results will be got with two sparks than with one. So far as we know no careful experiments have been made in this direction, but we have often wondered that for special purposes, when it has been tbe desire to get the utmost out of a given engine, the matter has not been pursued further, and three, or even four, sparking plugs placed in each cylinder. The advantage of dual ignition was found out long ago, so long ago that tbe majority of .motorists to-day have never beard of i1r. - Speaking from memory, it would be about 1898 or 1899 when, De Dion and Benz bavi1)g demonstrated the advantages of electric ignition, Panhard, DaimlE,r, a,nd one or two of the makers of large cars decided to try it in addition to the tube ignition, which they then fitted. Up to that time their cars had been provided with what·.would now be regarded as a ridiculously crude system of ignition. A platinum tube projected out of each cylinder sideways, and each tube wa.s heated by a little bunsen lamp, supplied from a separate petrol tank on the car. The timing of the ignition could not be varied when it \\"as once installed, except by varying the position of